Abstract: An aircraft comprises a fuselage, a plurality of support structures coupled to the fuselage, and a first propeller and a second propeller connected to a motor and symmetrically distributed along the plurality of support structures, the first propeller configured to create a first thrust having a first horizontal force vector and the second propeller configured to create a second thrust having a second horizontal force vector. A summation of the first and second horizontal force vectors is substantially zero when the first thrust is substantially equal to the second thrust, and a first rotational axis of the first propeller and a second rotational axis of the second propeller are substantially coplanar with a vertical axis disposed between the first and second propeller. A movement of the aircraft is controlled by selectively increasing or decreasing a thrust of either the first propeller or the second propeller.

Abstract: A vibration attenuator is configured for use on an aircraft rotor rotatable about a mast axis and has upper and lower weight assemblies, each comprising a weight with a center of gravity being a radial distance from the mast axis. The weight assemblies are configured for rotation together relative to the rotor at a selected angular rate about the mast axis, the weights being located on opposing sides of the mast axis. A first motor is configured for selective translation of one of the weight assemblies relative to the other weight assembly along the mast axis between a minimum-moment configuration, in which the centers of gravity of the weights revolve about the mast axis in the same plane, and a maximum-moment configuration, in which the centers of gravity of the weights revolve about the mast axis in different planes for producing a whirling moment about the mast axis.

Abstract: An electric reaction control system that can selectively expel a “burst” or “puff” of air to alter the orientation of the aircraft during flight. An aircraft incorporating ducting, an air compressor, an electric motor, and a plurality of nozzles can facilitate in-flight trajectory modifications. When an air burst is needed to provide thrust for the purposes of reaction control, nozzles are selectively opened and closed to provide roll, pitch, and yaw of the aircraft. The ERCS can facilitate an electric aircraft that would be very agile and very light, utilizing electric power, as opposed to jet power.

Abstract: A gimbaled rotor assembly for an aircraft. The gimbaled rotor assembly including a static mast; a spherical bearing comprising an inner component and an outer component pivotable relative to each other about a bearing focus, the inner component fixedly coupled to the static mast; a rotor hub rotatably coupled to the outer component, allowing for relative rotation of the rotor hub about a rotor axis and for pivoting together with the outer component about the bearing focus; and a primary hub spring coupling the outer component to the static mast and configured for opposing pivoting of the rotor hub about the bearing focus from a neutral position.

Abstract: A vibration attenuator has a first spinner configured for rotation about a first axis and a first mass coupled to the first spinner for rotation therewith, the first mass being movable radially relative to the first axis between an inner position and an outer position. An actuator is coupled to the first mass for selectively controlling a radial location of the first mass relative to the axis, and a first motor is configured for driving the first spinner in rotation about the first axis.

Abstract: An aircraft comprises a fuselage, one or more support structures connected to the fuselage, one or more engines or motors disposed within or attached to the one or more support structures or the fuselage, and a distributed propulsion system. The distributed propulsion system comprising two or more propellers symmetrically distributed in an array along the one or more support structures with respect to a center of gravity of the aircraft and operably connected to the one or more engines or motors, wherein each propeller has a rotation direction within a tilted plane of rotation, and a summation of horizontal force vectors created by the tilted plane of rotation of all the propellers is substantially zero when all the propellers are creating a substantially equal thrust magnitude. Movement of the aircraft is controlled by selectively increasing or decreasing a thrust of at least one of the two or more propellers.

Abstract: A vibration attenuator for a rotor of an aircraft has a first ring with an eccentric weight, a coaxial second ring with an eccentric weight, and a central ring coaxial with the first and second rings and located therebetween. A first post extends from the first ring toward the central ring and is received in a first arcuate groove formed on the central ring, whereas a second post extends from the second ring toward the central ring and is received in a second groove formed on the central ring. A motor is configured for driving the central ring in rotation about the axis relative to the motor. The grooves are equal in length, and a center of the first groove is located on an opposite side from a center of the second groove. Rotation of the central ring by the motor causes rotation of the first and second rings.

Abstract: A gimbaled rotor assembly for an aircraft. The gimbaled rotor assembly including a static mast; a spherical bearing comprising an inner component and an outer component pivotable relative to each other about a bearing focus, the inner component fixedly coupled to the static mast; a rotor hub rotatably coupled to the outer component, allowing for relative rotation of the rotor hub about a rotor axis and for pivoting together with the outer component about the bearing focus; and a primary hub spring coupling the outer component to the static mast and configured for opposing pivoting of the rotor hub about the bearing focus from a neutral position.

Abstract: In an implementation, the compound helicopter may include at least one rotary wing system, at least one first power generator and at least one second power generator. The at least one first power generator may rotate the at least one rotary wing blade to provide lift and a primary thrust force in a first direction to the helicopter. The at least one second power generator may be connected to the helicopter and may provide lift and a secondary thrust force in a direction that is independent of a direction of the primary thrust force and may also provide a secondary thrust force in a direction that is substantially parallel to the primary thrust force.

Abstract: A vibration attenuator for a rotor of an aircraft has a first ring with an eccentric weight, a coaxial second ring with an eccentric weight, and a central ring coaxial with the first and second rings and located therebetween. A first post extends from the first ring toward the central ring and is received in a first arcuate groove formed on the central ring, whereas a second post extends from the second ring toward the central ring and is received in a second groove formed on the central ring. A motor is configured for driving the central ring in rotation about the axis relative to the motor. The grooves are equal in length, and a center of the first groove is located on an opposite side from a center of the second groove. Rotation of the central ring by the motor causes rotation of the first and second rings.

Abstract: A vibration attenuator is configured for use on an aircraft rotor rotatable about a mast axis and has upper and lower weight assemblies, each comprising a weight with a center of gravity being a radial distance from the mast axis. The weight assemblies are configured for rotation together relative to the rotor at a selected angular rate about the mast axis, the weights being located on opposing sides of the mast axis. A first motor is configured for selective translation of one of the weight assemblies relative to the other weight assembly along the mast axis between a minimum-moment configuration, in which the centers of gravity of the weights revolve about the mast axis in the same plane, and a maximum-moment configuration, in which the centers of gravity of the weights revolve about the mast axis in different planes for producing a whirling moment about the mast axis.

Abstract: A vibration attenuator for a rotor of an aircraft has a track housing adapted for rotation relative to the rotor and configured for rotation at a second angular velocity greater than a first angular velocity of the rotor. A track is located within the track housing and has a reaction surface, a pair of weights being configured for movement within the track and in contact with the reaction surface. A stop assembly has a pair of stops spaced 180 degrees apart, the stops separating the weights from each other, and each weight being allowed to travel within the track between the stops. A motor rotates the track housing relative to the rotor. The weights are free to travel relative to each other between a minimum-force configuration, in which the weights are positioned 180 degrees apart, and a maximum-force configuration, in which both weights are adjacent one of the stops.

Abstract: A vibration attenuator for an aircraft has first and second coaxial spinners configured for rotation about a mast axis and relative to a rotor. Upper and lower weights of each spinner are spaced radially from the axis and positioned 180 degrees from each other about the axis. The weights of each spinner are spaced from each other a distance parallel to the mast axis, each weight rotating about the mast axis in a different plane. The spinners rotate together relative to the rotor at a selected angular rate and are selectively rotatable relative to each other between a minimum-moment configuration, in which the upper weight of each spinner is angularly aligned with the lower weight of the other spinner, and a maximum-moment configuration, in which the upper weights are angularly aligned and the lower weights are angularly aligned, producing a whirling moment about the mast axis as the spinners rotate.

Abstract: An aircraft comprises a fuselage, one or more support structures connected to the fuselage, one or more engines or motors disposed within or attached to the one or more support structures or the fuselage, and a distributed propulsion system. The distributed propulsion system comprising two or more propellers symmetrically distributed in an array along the one or more support structures with respect to a center of gravity of the aircraft and operably connected to the one or more engines or motors, wherein each propeller has a rotation direction within a tilted plane of rotation, and a summation of horizontal force vectors created by the tilted plane of rotation of all the propellers is substantially zero when all the propellers are creating a substantially equal thrust magnitude. Movement of the aircraft is controlled by selectively increasing or decreasing a thrust of at least one of the two or more propellers.

Abstract: A vibration attenuation system as shown and described.

Abstract: A vibration attenuator for a rotor is rotatable about a mast axis and has a frame configured for rotation about the mast axis relative to the rotor. A first mass is axially translatable in a first direction relative to the frame parallel to a first axis, and a first biasing force urges the first mass toward a first-mass rest position in which the first mass is symmetric about the mast axis. A second mass is axially translatable in a second direction relative to the frame parallel to a second axis, and a second biasing force urges the second mass toward a second-mass rest position in which the second mass is symmetric about the mast axis. A selected first or second mass moves radially outward from the rest position to oppose vibrations in the rotor.

Abstract: A vibration attenuation system for attenuating vibrations in a mast of an aircraft includes a weight attached to the mast but free to orbit about the mast. The weight can be comprised of one or more weight assemblies. Embodiments can include a single weight, or plural weight assemblies wherein each weight assembly can include a mechanical interconnecting mechanism so that each weight assembly receives feedback regarding the position and movement of one or more other weight assemblies. Each weight can be associated with a spring that urges the weight towards a neutral position. Rotation of the mast can cause the weight to orbit about the mast and self-excite such that the weight acts against the urging of the spring towards an attenuating position.

Abstract: An aircraft comprises a fuselage, one or more support structures connected to the fuselage, one or more engines or motors disposed within or attached to the one or more support structures or the fuselage, and a distributed propulsion system. The distributed propulsion system comprising two or more propellers symmetrically distributed in an array along the one or more support structures with respect to a center of gravity of the aircraft and operably connected to the one or more engines or motors, wherein each propeller has a rotation direction within a tilted plane of rotation, and a summation of horizontal force vectors created by the tilted plane of rotation of all the propellers is substantially zero when all the propellers are creating a substantially equal thrust magnitude. Movement of the aircraft is controlled by selectively increasing or decreasing a thrust of at least one of the two or more propellers.

Abstract: In some examples, an aircraft comprises an airframe, a rotor system coupled to the airframe, and a vibration attenuation system. The rotor system is operable to exert a vibratory force on the airframe. The vibration attenuation system comprises two or more batteries and elastic devices. The two or more batteries are operable to supply power to the rotor system. The elastic devices coupled to the two or more batteries and the airframe. The elastic devices are configured to attenuate the vibratory force based on facilitating oscillation of the two or more batteries. In other examples, a method comprises coupling elastic devices to two or more batteries and an airframe of an aircraft. The elastic devices receiving a vibratory force via the airframe and attenuate the vibratory force based on facilitating oscillation of the two or more batteries.

Abstract: A vibration attenuation system for attenuating vibrations in a mast of an aircraft includes a weight attached to the mast but free to orbit about the mast. The weight can be comprised of one or more weight assemblies. Embodiments can include a single weight, or plural weight assemblies wherein each weight assembly can include a mechanical interconnecting mechanism so that each weight assembly receives feedback regarding the position and movement of one or more other weight assemblies. Each weight can be associated with a spring that urges the weight towards a neutral position. Rotation of the mast can cause the weight to orbit about the mast and self-excite such that the weight acts against the urging of the spring towards an attenuating position.